The field of the invention is improved machines for riveting, staking, or the like including means for supporting a flexible sheet such as a ceramic, phenolic, or glass filled epoxy printed circuit board during the process of inserting and staking a rivet or other fastening device, more specifically, the supporting means is especially adapted to support the area about a rivet receiving opening without subjecting the circuit board to destructive bending loads. It has been a problem with thin sheets of brittle material which are used for electronic circuit boards (particularly those having thin films for circuit components) to adequately support them during a riveting operation without damaging or distorting them. Moreover, varying ambient conditions, residual stresses, and other processing variables may create warpage and dimensional errors which vary circuit board to circuit board. In a riveting operation, sheet warpage is a particularly troublesome problem since supporting a warped board requires an adaptable clamping device.
Machines are available which automatically position a circuit board transverse to the axis of reciprocable riveting apparatus and with holes in the board in alignment with the punch and anvil of such riveting apparatus by means of computer or numerical control. That is to say that, the circuit boards are automatically moved and aligned with the axis of a riveting punch and anvil so that each rivet-receiving-opening can be automatically filled in sequence. Because circuit boards may be warped and may already have other components carried thereon, the automatic machines support the boards at their edges and the punch and anvil are held apart from each other during transportation of the board to avoid interference with the installed components. Consequently, it is impractical to provide significant support at or near the rivet receiving openings until clamping just prior to riveting.